China's Communist leaders have dealt a hammer blow to the disgraced politician Bo Xilai, expelling him from the party and accusing him of everything from corruption to improper sexual behaviour as they seek to clear the stage for a November leadership handover.

The state news agency Xinhua said the flamboyant leader now faced criminal charges. It alleged that he took huge bribes and abused his power, bore "major responsibility" in relation to his wife's murder of a British businessman, maintained sexual relationships with several women and was involved in unspecified other offences.

The decision by the 25-member politburo, to which Bo himself once belonged, means he is destined to face the biggest political court case since the show trial of the Gang of Four in 1981, following the Cultural Revolution. While others of his rank have stood trial, none have had such influence.

The scandal surrounding his family, which led to his wife Gu Kailai's conviction last month for the murder of Neil Heywood, has overshadowed this year's transition of power to a new generation of leaders, marked by the 18th party congress, which Xinhua announced will start on 8 November.

Some think that the party will want to conclude Bo's case before the handover. But Cheng Li, an analyst at the Brookings Institution, suggested that this would be difficult because the politburo's decision to expel him should be ratified at a party gathering set for 1 November, and it was very unlikely authorities would put him on trial until that was done.

The 63-year-old former party secretary of Chongqing was once tipped for higher office in this autumn's handover. Many in China – particularly among neo-Maoists and in his former strongholds of Dalian and Chongqing – are privately sceptical about the true causes of his ousting, suggesting corruption and power abuses alone are insufficient to unseat senior leaders. His obvious ambition alienated many in the party.

"I have doubts on any criminal wrongdoings of Bo Xilai. I need to see the evidence … I think this is a political battle turned into a criminal one," said Han Deqiang, an economics professor at a Beijing university and a well known figure on China's left.

Rana Mitter, an expert on Chinese politics at Oxford University, told Associated Press: "They want to drive a stake through the heart of his political career, and make it absolutely impossible, not only for him to reappear but for anyone else who has that idea of trying to create that sort of personalised, political, charismatic leadership in some part of China which may challenge the leadership."

Chongqing's former police chief, Wang Lijun, precipitated his former patron's fall when he fled to an American consulate and announced he believed Gu had killed Heywood. He has been convicted of defection, helping to cover up the murder and other crimes.

Xinhua said Bo "bore major responsibility" in Wang's and Gu's cases but did not specify how. It said he sought profits for others and took huge bribes personally and via relatives, and his family accepted a huge amount of money and property because his wife abused his position. It added that he had made wrong choices in promoting people, "leading to serious consequences".

His serious violations of party discipline dated back even to his time as mayor of Dalian more than a decade ago, it said. His actions had damaged the cause of the party and the people and undermined the image of the party and China.

Bo had not been mentioned by name since the spring, when he was placed under internal party investigation. That, allied with the long wait for the announcement of the congress, prompted speculation about disagreements among senior leaders. Steve Tsang, an expert on Chinese politics at Nottingham University, noted: "The fact they can agree on a solution over Bo Xilai suggests they have come to some sort of general agreement."

Many analysts had thought leaders would be reluctant to try Bo because of his connections as the "princeling" son of a revered revolutionary leader, his enduring popularity in some quarters and the questions it would raise about leaders in general.

Tsang suggested the authorities might hold the hearings entirely behind closed doors if they feared Bo might use the trial to fight back. Wang and Gu had no reason to use their trials as "political theatre", because it could have brought tougher sentences. "The chances of [Bo] having a comeback are practically zero and he's not going to get a bullet through the head . How much difference can it make whether he gets 15 years or zero? He might well decide he didn't want to play ball," said Tsang.

But Li noted Xinhua's claim that the party investigation had found clues to his suspected involvement in other crimes. "This is the most important card in playing against Bo: 'If you do not co-operate – if you do not confess – if you make too much noise – then we have other things we can use'. I'm not saying they will use it; the chances are slim. But they certainly want to use it as a card," he said.